Es Werde Lichtstrom! Germany runs on solar for 2 full hours

Élan Vital
2012-05-28

The German solar power grid is among the world’s densest and fastest-growing. They have doubled their capacity for each of the last 10 years, and currently average 25% of all their power from the sun.

This has so far led to a 10% drop in the average price of power on their electricity exchange, thanks to the institution of “merit order” power supply: in which the lowest marginal-cost power is used first at any given moment. However the tremendous growth and success of solar power means they will soon have to cope with an unusual problem for modern national energy grids: storing excess renewable power. (Spain and Portugal have faced similar surplusses thanks to their tremendous wind power grids.)

They recently hit a few milestones: they set the world record for national solar generation (22GW), meeting fully half of the national energy demand. And for two hours, around midday Saturday, their solar output exceeded the national energy demand for the first time, for two hours.

I’d like to see more detailed data on all of this. The annual doubling of solar generation is fantastic and must involve extensive retooling of many subsidiary systems and capacity networks. How centralized/localized are those solar sources? Some data sources say national power production in Germany averages close to 70GW year-round, others claim a peak power draw of 50GW in the winter.

I’d also like to hear more about the limits of pumped energy storage and other uses of excess generated power. We could certainly generate an annual energy surplus for the planet if we tried to; but where’s that market in energy futures, and how much of an energy reservoir could we build up? What are other denser, more robust long-term ways to store power?